WASHINGTON (AP) — Former technology executive Carly Fiorina announced she's running for president, and retired neurosurgeon Ben Carson is set to launch his bid on Monday, as the Republican field of hopefuls expands once more. Both Fiorina and Carson have the potential to help the GOP win over a more diverse group of supporters in 2016.

Fiorina is likely to be the only prominent woman to seek the GOP nomination, with Carson the only likely African-American. They are both also political outsiders in a field likely to be dominated by governors, former governors and senators.

The two are not considered political allies and the timing of their announcements, planned weeks ago, is coincidental.

Fiorina, 60, chose the venue of a nationally broadcast morning network news show to announce her candidacy, and she also posted a video.

The former chief executive of Hewlett-Packard Co., appearing on ABC's "Good Morning America," said she understands "executive decision-making."

She also directly criticized Democrat Hillary Rodham Clinton, the front-runner for her party's nomination.

"I have a lot of admiration for Hillary Clinton, but she clearly is not trustworthy," Fiorina said, after confirming her plans to seek the presidency. She went after Clinton by name when asked, citing what she called a lack of transparency on a number of fronts, including the 2012 attack on an American embassy in Benghazi, Libya, Clinton's use of a private email server while secretary of state, and foreign donations to the Clinton Foundation.

Carson also got ahead of himself on Sunday, confirming his plans to run in an interview that aired on an Ohio television station.

"I'm willing to be part of the equation and therefore, I'm announcing my candidacy for president of the United States of America," he told WKRC-TV in Cincinnati.

Carson, 63, is scheduled to make his formal announcement Monday in a speech from his native Detroit shortly after having breakfast at a local museum of African-American history.

Both candidates begin the race as underdogs in a campaign expected to feature several seasoned politicians, among them former Florida Gov. Jeb Bush, Wisconsin Gov. Scott Walker, along with Florida Sen. Marco Rubio and Texas Sen. Ted Cruz. Yet while they have claimed much of the early attention and favor from donors, the GOP race is a wide-open contest that could ultimately feature as many as two dozen major candidates.

The Republican field is already more diverse than it was four years ago. Fiorina and Carson will compete against Republican counterparts Rubio and Cruz, each vying to become the first Hispanic president. And most of the candidates are in their 40s and 50s.

Still, the Republican National Committee has acknowledged a pressing need to broaden the party's appeal beyond its traditional base of older, white men. President Barack Obama won re-election in 2012 with the strong support of women and ethnic minorities, who are becoming a larger portion of the American electorate.

Raised in Detroit by a single mother, Carson practiced medicine and served as the head of pediatric neurosurgery for close to three decades at Baltimore's Johns Hopkins Children's Center. He gained national renown in conservative politics after condemning Obama's health care law at the 2013 national prayer breakfast.

He has established a strong base of vocal support among tea party-backers, some of whom launched an effort to push Carson into the race before he set up an exploratory committee earlier this year.

Yet he has stumbled at times in the glare of national politics. He has suggested the Affordable Care Act is the worst thing since slavery, compared present-day America to Nazi Germany, and called problems at the nation's Veterans Affairs hospitals "a gift from God" because they revealed holes in country's effort to care for former members of the military.

Fiorina, meanwhile, has a resume more likely to draw support among the Republican establishment. The former chief executive of Hewlett-Packard Co., she became a prominent figure in Republican politics in 2010, when she ran for Senate in California and lost to incumbent Sen. Barbara Boxer by 10 points.

In the past several months, she has emerged as a fierce critic of Hillary Rodham Clinton, the front-runner for the Democratic nomination, whose potential to become the nation's first female president is a centerpiece of her political brand.

Both Carson and Fiorina immediately launch national tours in early voting states.

Carson is scheduled to spend the first three days of his presidential campaign in Iowa, before heading to South Carolina at the end of the week and New Hampshire and Nevada the next.

Fiorina's first post-announcement public event is scheduled for Tuesday in New York City, although she will campaign in Iowa, New Hampshire and South Carolina by week's end.